Methods and systems for aligning tooling elements of ultrasonic bonding systems

ABSTRACT

A method of aligning a subject tooling element of a material handling system of an ultrasonic bonding system is provided. The method includes the steps of: a) providing an overlay defining a relative position of at least a portion of a reference tooling element; b) viewing an image of at least a portion of the subject tooling element combined with a corresponding portion of the overlay; and c) adjusting a position of at least a portion of the subject tooling element by referring to the overlay in the image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of application Ser. No.13/884,419, filed May 9, 2013, which claims the benefit of InternationalPCT Application No. PCT/US2011/066428, filed Dec. 21, 2011, which claimsthe benefit of U.S. Provisional Application No. 61/428,047, filed onDec. 29, 2010, the content of each of which is incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to ultrasonic bonding systems, and moreparticularly, to methods of aligning tooling elements of such systems.

BACKGROUND OF THE INVENTION

In the processing and packaging of semiconductor devices, ultrasonicbonding (e.g., wire bonding, ribbon bonding, etc.) continues to be awidely used method of providing electrical interconnection between twoor more locations within a package (e.g., between a die pad of asemiconductor die and a lead of a leadframe). For example, wire bondingmachines are used to form wire interconnections between respectivelocations to be electrically interconnected. In certain exampleultrasonic bonding systems, an upper terminal end of a bonding tool isengaged in an ultrasonic transducer. The transducer vibrates the bondingtool resulting in bond formation between a portion of the wire and abonding location (e.g., a bond pad, a lead of a leadframe, etc.).

During a wire or ribbon bonding operation the workpiece (e.g., aleadframe strip including a plurality of semiconductor die) is supportedby a support structure (e.g., a support anvil, a heat block, etc.). Theworkpiece is indexed using a material handling system to position aportion of the workpiece (e.g., a column of semiconductor die) over thesupport structure. The workpiece is typically secured between thesupport structure and a clamping structure. In a specific example, thesupport structure raises the relevant portion of the workpiece aboverails of the material handling system, and the clamping structure islowered to secure the workpiece against the support structure. Such aclamping structure may include a plurality of clamping fingers forcontacting various portions of the workpiece.

It is important that the support structure and clamping structure beproperly positioned during bonding. The process of properly positioningthe support structure and clamping structure can be difficult and timeconsuming, especially in applications where multiple clamping fingersare included in the clamping structure. An exemplary conventional methodof aligning these structures includes use of mechanical dies/gaugesspecific to the workpiece. Such dies/gauges tend to be expensive tomanufacture, and are limited to use by a single bonding system, and asingle type of workpiece.

Thus, it would be desirable to provide improved systems and methods foraligning tooling elements of ultrasonic bonding systems.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the present invention, a methodof aligning a subject tooling element of a material handling system ofan ultrasonic bonding system is provided. The method includes the stepsof: a) providing an overlay defining a relative position of at least aportion of a reference tooling element (e.g., a relative position“relative” to another location of a reference bonding system such as thea reference position of a reference material handling system); b)viewing an image of at least a portion of the subject tooling elementcombined with a corresponding portion of the overlay; and c) adjusting aposition of at least a portion of the subject tooling element byreferring to the overlay in the image. Examples of the subject toolingelement include (1) a subject support structure configured to support aworkpiece during an ultrasonic bonding operation, and (2) at least oneclamp finger of the material handling system.

According to another exemplary embodiment of the present invention, amethod of generating an overlay of at least a portion of a toolingelement of a material handling system of an ultrasonic bonding system isprovided. The method includes the steps of: (a) aligning at least theportion of the tooling element with respect to a workpiece; and (b)creating the overlay to include at least one marking identifying aposition of at least the portion of the tooling element after step (a).

According to yet another exemplary embodiment of the present invention,an ultrasonic bonding system is provided (e.g., the ultrasonic bondingsystem shown in FIG. 8, etc.). The machine includes a support structureconfigured to support a workpiece during an ultrasonic bondingoperation, and a clamp finger for securing a portion of the workpieceagainst the support structure during the ultrasonic bonding operation.The machine also includes an imaging system, and an overlay configuredto be imaged by the imaging system in relation to at least one of thesupport structure and the clamp finger. These features (as well as otherfeatures of such a system) are shown and described in connection withthe various figures provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawings. It is emphasizedthat, according to common practice, the various features of the drawingsare not to scale. On the contrary, the dimensions of the variousfeatures are arbitrarily expanded or reduced for clarity. Included inthe drawings are the following figures:

FIG. 1A is an overhead block diagram view of a portion of a materialhandling system of an ultrasonic bonding machine useful for explainingvarious exemplary embodiments of the present invention;

FIG. 1B is a cut away view of FIG. 1A taken along line 1B-1B;

FIG. 2A is a perspective block diagram view of a support structure of amaterial handling system useful for explaining various exemplaryembodiments of the present invention;

FIG. 2B is an end view of FIG. 2A;

FIG. 3A is an overhead block diagram view of the material handlingsystem of FIG. 1A, incorporating the support structure of FIGS. 2A-2B,useful for explaining various exemplary embodiments of the presentinvention;

FIG. 3B is a cut away view of FIG. 3A taken along lines 3B-3B;

FIG. 4 is an overhead block diagram view of a leadframe useful forexplaining various exemplary embodiments of the present invention;

FIG. 5A is an overhead block diagram view of a material handling systemof FIG. 3A including the leadframe of FIG. 4, useful for explainingvarious exemplary embodiments of the present invention;

FIG. 5B is a cut away view of FIG. 5A taken along lines 5B-5B;

FIG. 5C is an enlarged block diagram view of portion 5C of FIG. 5Aincluding additional features of the material handling system;

FIG. 5D is an enlarged block diagram view of portion 5C of FIG. 5Aincluding additional features of the material handling system, andreference locations in accordance with an exemplary embodiment of thepresent invention;

FIG. 5E is two enlarged portions 5E of FIG. 5D;

FIG. 5F is an enlarged block diagram view of portion 5C of FIG. 5Aincluding additional features of the material handling system, andalternative reference locations in accordance with an exemplaryembodiment of the present invention;

FIG. 5G is two enlarged portions 5G of FIG. 5F;

FIG. 5H is an overhead block diagram view of a graphical overlayincluding overlay markings superimposed on a portion of an ultrasonicbonding system in accordance with an exemplary embodiment of the presentinvention;

FIG. 5I is an overhead block diagram view of a graphical overlayincluding overlay markings superimposed on a portion of an ultrasonicbonding system in accordance with another exemplary embodiment of thepresent invention;

FIG. 5J is an overhead block diagram view of a graphical overlayincluding overlay tolerance field markings superimposed on a portion ofan ultrasonic bonding system in accordance with another exemplaryembodiment of the present invention;

FIG. 5K is an overhead block diagram view of the graphical overlay ofFIG. 5H in accordance with an exemplary embodiment of the presentinvention;

FIG. 6A-6D are block diagram views of multiple layers of the graphicaloverlay of FIG. 5H in accordance with an exemplary embodiment of thepresent invention;

FIG. 7A is an overhead block diagram view of a portion of a materialhandling system illustrating reference locations and respectivesnapshots of those reference locations in accordance with an exemplaryembodiment of the present invention;

FIG. 7B is an overhead block diagram view of a graphical overlaysuperimposed upon tooling elements of a material handling system inaccordance with an exemplary embodiment of the present invention;

FIG. 7C is an enlarged view of portion 7C of FIG. 7B;

FIG. 7D is an enlarged view of portion 7D of FIG. 7G;

FIG. 7E is an enlarged view of portion 7E of FIG. 7B;

FIG. 7F is an enlarged view of portion 7F of FIG. 7G;

FIG. 7G is an overhead block diagram view of the graphical overlay ofFIG. 7B with tooling elements of the material handling system nowaligned with the graphical overlay in accordance with an exemplaryembodiment of the present invention;

FIG. 7H is an overhead block diagram view of FIG. 7G now including aleadframe in accordance with an exemplary embodiment of the presentinvention; and

FIG. 8 is a side block diagram view of various elements of an ultrasonicbonding system useful for explaining various exemplary embodiments ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein the term “overlay” is intended to refer to any marks orother indicia which may be viewed in connection with an optical image ofa portion of an ultrasonic bonding machine. Exemplary overlays arecomputerized overlays described herein which include computerizedmarkings on a display that may be viewed by an operator of an ultrasonicbonding machine and/or workpiece.

As used herein, the term “tooling element” is intended to refer to anyportion of an ultrasonic bonding machine used to support, restrain,and/or contact a workpiece during a wire/ribbon bonding operation. Anexemplary tooling element includes a support structure (e.g., an anvil)configured to support a workpiece (e.g., from below the workpiece)during an ultrasonic bonding operation. Another exemplary toolingelement is a device clamp including clamping fingers for contactingand/or restraining portions of the workpiece (e.g., leadframe) duringthe wire/ribbon bonding operation.

FIGS. 1A-1B illustrate a portion of material handling system (MHS) 100(sometimes referred to as a transport box) of an ultrasonic bondingmachine (e.g., an ultrasonic wire bonding machine, or an ultrasonicribbon bonding machine). Workpieces to be bonded (e.g., leadframes to bewire bonded) are moved along front and back rails 102, 104 of MHS 100(e.g., using gripping members, pushing members, pulling members, etc.).MHS 100 also includes support structure riser (e.g., anvil riser) 112.Riser 112 is configured to raise and lower a support structure (e.g., ananvil), where the support structure supports a workpiece during abonding operation. A position of front rail 104 may be adjusted (e.g.,along the y-axis, see arrow 114) to accommodate varying sizes ofworkpieces. Riser 112 defines holes 190 which may be used to secure asupport structure (e.g., an anvil) to top surface 112 a of riser 112(e.g., see anvil 220 in FIGS. 2A-2B).

As explained below, reference locations/positions may be identified onan MHS system. Exemplary locations on MHS 100 that may be used as suchreference locations include (1) notch 110 in back rail 102, (2) indicia108 on back rail 102 (e.g., a string of characters positioned on backrail 102), (3) one of holes 190, amongst other locations.

As more clearly illustrated in FIG. 1B (taken along line 1B-1B with somedetail removed for simplicity), rails 102, 104 define respective lips102 a, 104 a for supporting a workpiece (e.g., leadframe) during travelalong MHS 100. Of course, other types of rails are contemplated.

FIGS. 2A-2B illustrate support structure 220 (e.g., anvil 220)configured to be carried by riser 112. During a bonding operation, anvil220 supports a portion of a workpiece. Anvil 220 includes a lower base222, and an upper face 224 for supporting the workpiece.

FIGS. 3A-3B are views of MHS 100 of FIG. 1 with support structure 220secured to riser 112 by lockdown plates 330. Fasteners 306 are used tosecure lockdown plates 330 to riser 112 through engagement with ones ofholes 190. Of course, other support structure designs are contemplated.

FIG. 4 illustrates exemplary leadframe 440 that is indexed using MHS 100of the ultrasonic bonding machine. Leadframe 440 includes a plurality ofdie 446 separated by, and connected by, tie bars 444 and leads 442.

FIGS. 5A-5B illustrates MHS 100 shown in FIG. 3A (including supportstructure 220), with leadframe 440 indexed to a position over anvil face224 for bonding. Leadframe 440 is positioned against a benching edge ofback rail 102 to fix its position with respect to back rail 102 alongthe y-axis. Three semiconductor die 446 (arranged in a column) are shownpositioned over face 224 of anvil 220. As more clearly seen in FIG. 5B,anvil riser 112 has been raised (e.g., using a cam system or othermotion system) such that anvil face 224 is above plane 550 defined byrail lips 102 a, 104A. In this position, anvil 220 supports the threedie 446 (each supported by respective heat sink 448) within portion 5Cof FIG. 5A, and a clamping structure (e.g., a device clamp includingclamping fingers as described below) may be lowered to secure thatportion of leadframe 440 against anvil 220.

FIG. 5C illustrates portion 5C of FIG. 5A. Die 446 are supported byrespective heat sinks 448 (e.g., where heat sinks 448 are portions ofleadframe 440). Leads 442 and tie bars 444 connect to heat sink 448.Device clamp 556 has been positioned over leadframe 440 so that clampingfingers 554 of device clamp 556 contact various portions of leadframe440 (e.g., leads 442, tie bars 444, etc.) to secure leadframe 440against anvil 220. Thus, FIG. 5C may be considered a desirable set upfor the tooling element (i.e., the anvil and the clamping fingers arealigned in desirable positions with respect to an indexing position ofthe leadframe). It would be desirable if the set up of the elementsshown in FIG. 5C could be replicated during future bonding operations oflike workpieces on the same or different wire bonding machines. FIGS.5D-5K illustrate exemplary techniques for generating an alignmentoverlay.

FIG. 5D is similar to the view of FIG. 5C but also illustrates certainadditional features of MHS 100 (including front rail 104, holes 190 ofriser 112, and back rail 102 defining notch 110). In order to generatean alignment overlay of at least a portion of the tooling element (e.g.,clamping fingers of a device clamp, a support structure such as ananvil, etc.), set-up software is initiated (e.g., Graphical ToolingSet-up Software). In accordance with the set-up software, at least onereference location/point is selected. For example, the referencelocation(s) may be: a location(s) of a portion(s) of a referencematerial handling system (e.g., such as MHS 100 shown in FIG. 5D); alocation(s) of a portion(s) of a workpiece (e.g., areas of leadframe 440shown in FIG. 5D); etc. In FIG. 5D, exemplary reference locations 562and 564 have been selected as part of MHS 100. More specifically, firstMHS reference location 562 is defined (e.g., by the user) as the upperleft corner of notch 110 of back rail 102. Second MHS reference location564 is defined as the left most point of left hole 190 in anvil riser112.

As illustrated in FIG. 5E (consisting of snapshot A, and snapshot B), animage snapshot is taken of each defined MHS reference location 562, 564at portions 5E of FIG. 5D (e.g., snapshot A, snapshot B). For example,snapshots A and B are taken by the imaging system of MHS 100. Thisimaging system may be the same imaging system used during the bondingoperation for tasks such as pattern recognition operations, teachingoperations, etc. (or may be a distinct imaging system). Snapshots A(i.e., of the corner of notch 110 of back rail 103) and B (i.e., theleft most part of left hole 190) may be used later to locate theselected reference locations of a subject material handling system asdescribed below. While a single reference location may be selected, inmany applications it will be desirable to select at least two referencelocations to more accurately align the overlay with a subject MHS (e.g.,to avoid potential error introduced by rotation, etc.).

While FIG. 5D illustrates reference locations 562, 564 selected on MHS100, other reference locations may be selected. For example, referencelocations may be selected on a workpiece to be wire or ribbon bonded.Another non-limiting example would be to have one or more referencelocations on each of the MHS and the workpiece. FIG. 5F illustrates anexample where reference locations 566, 568 are selected on workpiece 440(e.g., as portions of leadframe 440). Of course, other locations on aworkpiece/leadframe may be selected. For example, FIG. 5F illustratesvarious optional reference locations 570.

Images/snapshots C, D are taken of respective leadframe referencelocations 566, 568 at portions 5G (e.g., see FIG. 5G illustratingenlarged views of snapshots C, D). If portions of a workpiece areselected as the reference locations, the workpiece (e.g., leadframe 440)may be positioned in a desired location for bonding such as in FIG. 5C,over support structure 220 and in relation to clamping fingers 554. Inthis position, reference locations 566, 568, 570 are selected (e.g., seeFIG. 5F), and position markings may be defined for the overlay (asdescribed below in connection with, e.g., FIGS. 5H-5I). Of course, ifthe overlay is to include position markings of the support structure(e.g., anvil 220) it may be useful to move the workpiece away from itsbonding position such that the support structure is visible in order todefine anvil position markings for the overlay.

Regardless of the source of the reference locations (e.g., the MHS, theworkpiece, etc.), the user may select the reference locations byaligning the imaging system in a position above the selectedlocation(s). For example, the user may move the imaging system (e.g.,including a camera) along the XY coordinate system of the bondingmachine using the XY table. When the imaging system is positioned abovethe selected reference location, the user specifies the selectedreference location (e.g., such as inserting a symbol on the location,drawing one or more lines on or proximate to the reference location,etc.), and the user takes a snapshot of the selected reference location.The XY location of the reference location is now known, and is stored inmemory. In a more specific example, the crosshairs of the lens of theimaging system may be aligned to intersect a point of the selectedreference location. The XY position of such a crosshair (or equivalentstructure) is known by the wire bonding machine and may be stored inmemory as a snapshot. Referring back to FIGS. 5D-5E, crosshair 572 ofthe imaging system lens is aligned at the corner of notch 110 to definereference location 562. By selecting this as a reference location, theXY position of the corner of notch 110 of the reference MHS is known. Ofcourse, while cross hair 572 is illustrated in two locations in FIG. 5Deach of these locations refers to an image taken at a different time.After obtaining (e.g., and storing in memory) the XY locations of thereference locations, the user may then define the markings for theoverlay in relation to the reference location(s) as will be describedbelow with respect to, for example, FIGS. 5H-5J. In connection with thecreation of the marking, the user may use certain drawing options suchas line color, line weight, etc.

FIG. 5H illustrates a graphical overlay including overlay markingssuperimposed on a portion of an ultrasonic bonding system. Morespecifically, since the tooling element (e.g., clamping fingers 554 andanvil 220) are in their desired positions for bonding on the referenceMHS/bonder, the user may now generate position markings for the overlay.That is, the user may position the imaging system to image portions ofclamping fingers 554 in turn, and create graphical overlay fingermarkings 560 for each clamping finger 554. For example, the software mayhave predefined shapes (e.g., graphical markings 560 in FIG. 5H, crossshapes such as cross-shaped position markings 560′ in FIG. 5I, toleranceshapes such as markings 560″ in FIG. 5J, etc.) to identify the positionmarkings. In another example, the software may allow the user tocustomize the shapes. Customized shapes may be drawn by the user line byline (or other markings such as boxes, arc shapes, etc.), to generatethe desired customized shape. A specific example of a customized shapemay be marking 560 that has a shape to approximate the outline of aportion of the tooling element such as clamp finger 554.

The user may generate the graphical position markings by a computerinput mechanism (e.g., a computer mouse, track ball, touch screen,stylus, keyboard, etc.). When the computer input mechanism is linked tothe XY position of the imaging system lens (e.g., camera lens), the XYposition of each graphical marking is known. That is, after thegraphical markings are created, their respective positions relative tothe XY coordinate system of the MHS/bonder (and also their positionrelative to the reference locations) are known and may be stored inmemory in connection with the graphical overlay. Referring again to FIG.5H, the user has created (or otherwise provided) respective graphicalmarkings 560 to mark the desired position of each clamping finger 554 inthe MHS/bonder XY coordinate system. Further, the user has also createdgraphical anvil markings 558 to mark the desired position of portions ofanvil 220. Collectively, these markings 558, 560 represent graphicaloverlay 580 shown in FIG. 5K (shown apart from tooling elements 220, 554in FIG. 5J). That is, after overlay 580 is generated, it may be viewedin portions visible in field of view (FOV) 574 of the imaging system(and subject to scaling of the imaging system and similar functions).Specifically, graphical overlay 580 may be fixed with respect to theimaging system and does not move when the imaging system (e.g., acamera) is moved over the MHS/workpiece.

FIG. 5H illustrates an example where graphical markings 560, 558 arecustomized to approximate the outline of a portion of each clamp finger554 and anvil 220; however, any type of marking may be selected asdesired. For example, FIG. 5I illustrates cross-shaped graphicalmarkings 560′ to denote the positions of each clamp finger (and anvil220). More specifically, graphical overlay clamping finger markings 560′define a corner configured for alignment with a portion of a respectiveend of clamping fingers 554, and graphical overlay anvil markings 558′define opposing corners configured for alignment with a respectiveportion of anvil 220.

FIG. 5J illustrates an example where graphical tolerance field markings560″ are provided (as opposed to the markings shown in FIGS. 5H-5I) suchthat when a predetermined portion of each clamp finger 554 falls withina respective tolerance field marking 560″, they may be considered to besufficiently aligned. For example, FIG. 5J illustrates square shapedgraphical tolerance field markings 560″, where each corner portion 554 ahas been aligned to be within a respective one of markings 560″.Likewise, opposing corner points 220 a of anvil 220 have been alignedwithin a respective one of tolerance markings 558″. The size, shape andorientation of graphical tolerance field markings 560″, 558″ may bechanged as desired. Exemplary variations include circle shaped tolerancemarkings, opposing lines defining a tolerance range (i.e., not a closedshape), amongst others.

Such graphical tolerance field markings 560″, 558″ may permit alignmentof clamping fingers 554 and/or anvil 220 within such tolerance limits.That is, if an end portion of clamping finger 554 is within itsrespective graphical tolerance field marking 560″, that clamping finger554 may be deemed as aligned.

FIG. 5K illustrates an exemplary single viewable overlay 580 includinggraphical markings 558, 560 for tooling elements 220, 554 (e.g., seeFIG. 5H). It may be desirable to divide overlay 580 into portions, or“layers”, to simplify use of overlay 580 by a machine operator. Oneexemplary technique for dividing the portions of the tooling element(e.g., anvil 220, groups of clamping fingers 554, etc.) is based uponthe height (e.g., along the z-axis) of each portion of the toolingelement. In connection with such a technique, each layer of the overlay(corresponding to the heights of portions of the tooling element) mayhave a corresponding focus height setting of the imaging device (e.g., aheight along the z-axis of the imaging device); that is, with thespecific focus height setting for that layer, the corresponding portions220, 554 of the tooling element are in focus. In one more specificexample, the imaging device is moved along the z-axis (along with thebond head) to compensate for variations in heights of portions 220, 554of the tooling element, thereby providing a consistent focal length.

FIGS. 6A-6D illustrate an example where overlay 580 is provided as fourdistinct layers 580 a, 580 b, 580 c, 580 d (e.g., for different heightsof the subject portions of the tooling element, where each layer/toolingportion height may have its own focus height setting of the imagingdevice). FIG. 6A illustrates a first (e.g., lowest) layer 580 a ofgraphical overlay 580, and includes only graphical overlay anvilmarkings 558. FIG. 6B illustrates layer 580 b (e.g., the next layer upfrom layer 580 a) and includes the lowest level of graphical overlayclamping finger markings 560 a corresponding to the lowest level ofaligned clamping fingers 554 on leadframe 440. FIG. 6C illustrates layer580 c (e.g., the next layer up from layer 580 b) and includes graphicaloverlay clamping finger markings 560 b corresponding to the middle layerof aligned clamping fingers 554 on leadframe 440. FIG. 6D illustrateslayer 580 d (e.g., the next layer up from layer 580 c) and includesgraphical overlay clamping finger markings 560 c corresponding to theuppermost level of aligned clamping fingers 554 on leadframe 440.

Regardless of whether the overlay is a single layer (e.g., overlay 580),or a plurality of layers (e.g., layers 580 a, 580 b, 580 c, 580 d), theoverlay may now be stored in a memory of the ultrasonic bonding machine(or some other memory such as a portable memory device or networkedmemory), and may be otherwise electronically transmitted to another(e.g., remote) location for use in aligning the portions of the toolingelement as described below.

As provided above, FIGS. 5D-5K illustrate exemplary techniques forgenerating overlays that may be a unitary overlay 580, or an overlaycomprised of multiple overlay portions 580 a-580 d, that may eachcorrespond to a different (focal) height of a tooling element. Anexemplary use of graphic overlay 580 will now be described in connectionwith FIGS. 7A-7G. The user of overlay 580 may be the same user whogenerated overlay 580, or may be another user in a local or remotelocation. In any event, the software including the overlay is loadedinto active memory of (or accessible by) the bonding machine on which itwill be used to align the tooling element.

FIG. 7A illustrates snapshots A and B which the user may view in orderto identify the corresponding reference locations on the subject MHS.That is, it may be efficient to provide the user of subject MHS 700 witha view of the reference location(s) that were selected during generationof the overlay in order to identify the corresponding referencelocation(s) on subject MHS 700. In FIG. 7A (including anvil 720 andanvil lockdown plate 730), the user may use snapshot A to identifyreference location 562, and may use snapshot B to identify referencelocation 564 of material handling system 700. After the upper left handcorner of notch 710 has been identified as corresponding to thereference location in snapshot A, the imaging device is positioned toalign the imaging system (e.g., the cross hair of the lens of theimaging system) to notch 710 in back rail 702 as shown in FIG. 7A. Byaligning the imaging system with notch 710 as shown in FIG. 7A,reference location 562 is established. The position of referencelocation 562 in the XY coordinate system of the subject MHS/bonder isnow fixed (e.g., and saved to memory). This process may be repeated forany additional reference locations such as reference location 564 (e.g.,the left side of left hole 790 in subject anvil riser 712 proximatefront rail 704 as shown in FIG. 7A). After the position of the desiredreference locations (e.g., 562 and 564) are fixed in (e.g., and savedto) the subject MHS/bonder, the overlay may be aligned to the subjectMHS/bonder. For example, the XY position of each of the markings of theoverlay may be adjusted by the software based on the XY offset of thereference locations from the reference M HS/bonder to the subjectMHS/bonder. In any event, the markings of the overlay are now beavailable for viewing (e.g., on a display of the bonder) (and foraligning the portions of the tooling element) in connection with thesubject MHS bonder.

While FIG. 7A is illustrated and described in connection with a manualprocess of locating and aligning the reference locations from thereference MHS/bonder to the subject MHS/bonder, the present invention isnot limited thereto. That is, automated techniques may be used to locateand align the reference locations. In one example, pattern recognitiontechniques may be used to automatically align the reference location(s)and, if desired, to automatically generate the overlay based on thealigned reference location(s).

FIG. 7B illustrates a portion of a subject MHS having portions of thetooling element (e.g., anvil 720, and clamping fingers 774 of deviceclamp 776) misaligned with respect to graphical overlay markings 558,560 of overlay 580. Using graphical overlay 580 (or multiple layers 580a, 580 b, 580 c, 580 d, as desired), the imaging system may image eachdesired clamping finger 774 on a display, where the correspondingportion of overlay 580, including the corresponding alignment marking560, is superimposed within the image of the clamping finger 774. Thus,a user can look at the display and move each clamping finger 774, asnecessary, so that it is aligned with its corresponding alignmentmarking 560. This results in aligned clamping finger 774′ (e.g., seeFIGS. 7D and 7G). More specifically, FIG. 7C (portion 7C of FIG. 7B)illustrates an exemplary clamping finger 774 that is misaligned withrespect to alignment marking 560, and FIG. 7D (portion 7D of FIG. 7G)illustrates that exemplary clamping finger 774′ repositioned to bealigned with alignment marking 560. This process may be repeated foreach misaligned clamping finger 774. Likewise, this process may berepeated for misaligned anvil 770. More specifically, FIG. 7E (portion7E of FIG. 7B) illustrates an anvil 770 that is misaligned with respectto alignment marking 558, and FIG. 7F (portion 7F of FIG. 7G)illustrates anvil 770′ repositioned to be aligned with alignment marking558. The alignment of clamping fingers 774 and anvil 770 may occur inany order, as desired. FIG. 7G illustrates the tooling element havingits respective portions now aligned in accordance with overlay 580.

As noted above, the process of adjusting the portions of the toolingelement may be a manual process by which the user positions the imagingsystem to view each portion of the tooling element (along with thecorresponding alignment marking) in succession. However, the process maybe enhanced such that the imaging system automatically proceeds from onealignment marking to the next alignment marking upon a predeterminedcondition being met. For example, the predetermined condition may be akeystroke, button, etc. by which the user indicates that he/she is readyto view the next alignment marking (presumably along with thecorresponding portion of the tooling element).

Following the alignment process illustrated and described above withrespect to FIGS. 7A-7G, the user may then index a workpiece to a bondingposition on the subject MHS in order to confirm that the tooling element(including the clamping fingers and/or the anvil) is properly positionedwith respect to the workpiece. FIG. 7H illustrates a workpiece (i.e.,leadframe 740) indexed into a bonding position. Leadframe 740 isgenerally aligned with the tooling element (e.g., aligned clampingfingers 774′) as desired; however, if leadframe 740 is not properlyaligned, adjustments may be made. For example, the leadframe indexingmay be adjusted (e.g., along the x-axis, and possibly along the y-axis).Such adjustments may be made in software or hardware. Further, a portionof the tooling element may also be adjusted as desired (e.g., inconnection with an adjusted alignment marking/overlay). For example, theuser may adjust the positions of aligned anvil 720′, and alignedclamping fingers 774′, as desired to adjust the alignment with leadframe740. The user may then use the software to edit (and save) the overlay(e.g., unitary overlay 580, or layers 580 a, 580 b, 580 c, 580 dcomprising overlay 580) and/or the reference locations of overlay 580 tocorrespond to the adjusted anvil and clamping fingers positions.

FIG. 8 illustrates support structure 220 (e.g., anvil 220 with face 224)supporting workpiece 440 (e.g., leadframe 440 with die 446 supported byface 224). Other elements of the ultrasonic bonding system shown in FIG.8 include XY table 890 carrying bond head 894, which in turn carriesbonding tool 896 and optical system 892. Of course, other configurations(e.g., a configuration where optical system 892 can change the focusheight setting independent of movement of the bond head) arecontemplated. Optical system 892 defines optical axis 898, where opticalaxis 898 is offset from bonding tool axis 902 by offset 900. Anvil 220is raised above rail lip plane 550 and supports die 446 (the deviceclamp is omitted for simplicity). Optical system 892 may focus upondifferent portions of the tooling element (where the portions may bearranged at different heights) by changing a focus height setting. Thismay be accomplished by the z-axis movement of optical system 892 (inthis case carried by bond head 894) as shown by double headed arrow 904.Images from optical system 892 (e.g., including a camera) are displayedon display device 906 for viewing by the user, for example, during setupof the reference tooling element (including generation of the overlay)and during use of the overlay with respect to a subject tooling elementto be aligned.

In summary, the Graphical Tooling Setup Software (GTS) of the presentinvention uses an imaging capture system installed on a wire or ribbonbonder to create an image of the material handling system (MHS) on abonder. A graphical representation, or template, (e.g., graphicaloverlay 580) is then provided (e.g., superimposed) on this MHS image toallow for alignment of various elements of the tooling element to thisgraphical representation. The graphical representation is locatedrelative to distinguishing features on a workpiece (e.g., a leadframe)or MHS to allow for portability of the graphical template to multiplebonders/locations.

Although the present invention has been described primarily in terms ofbonding systems and workholders for bonding wire of ribbon materialbetween die and leads, it is not limited thereto. The teachings of thepresent invention have application in any of a number of ultrasonicbonding applications (e.g., ribbon bonding, wire bonding, etc.) to anyof a number of types of workpieces (not limited to leadframes).

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

What is claimed:
 1. A method of generating an overlay of at least aportion of a tooling element of a material handling system of anultrasonic bonding system, the method comprising the steps of: a)aligning at least the portion of the tooling element with respect to aworkpiece; and b) generating the overlay to include at least one markingidentifying a position of at least the portion of the tooling elementafter step a).
 2. The method of claim 1 wherein the at least one markingincludes at least one of (1) a cross-shaped marking, and (2) an outlinemarking of the portion of the tooling element.
 3. The method of claim 1wherein the at least one marking includes a tolerance marking, whereinthe tolerance marking defines a range within which the portion of asubject tooling element is configured to be aligned.
 4. The method ofclaim 1 wherein the tooling element includes a plurality of clampingfingers.
 5. The method of claim 1 wherein the tooling element includes asupport structure configured to support the workpiece in connection withan ultrasonic bonding operation.
 6. The method of claim 1 wherein thetooling element includes a plurality of clamping fingers and a supportstructure configured to support the workpiece in connection with anultrasonic bonding operation.
 7. The method of claim 1 wherein theworkpiece is a leadframe.
 8. The method of claim 1 further comprising astep of selecting at least one reference position on the materialhandling system for providing relative position information for the atleast one marking.
 9. The method of claim 8 further comprising the stepof imaging the at least one reference position.
 10. The method of claim8 wherein the at least one reference position is a position of at leastone of (1) a portion of a rail member of the material handling system,and (2) a portion of a riser member of the material handling systemconfigured for supporting the workpiece in connection with an ultrasonicbonding operation.
 11. The method of claim 8 wherein the at least onereference position is a plurality of reference positions.
 12. The methodof claim 1 further comprising a step of selecting at least one referenceposition on the workpiece to provide relative position information forthe at least one marking, wherein the workpiece is positioned by thematerial handling system of the ultrasonic bonding system.
 13. Themethod of claim 12 wherein the at least one reference position is aplurality of reference positions.
 14. The method of claim 12 wherein theworkpiece is a leadframe.
 15. The method of claim 12 further includingthe step of imaging the at least one reference position.
 16. The methodof claim 1 wherein step b) includes creating the overlay to include theat least one marking identifying the position of at least the portion ofthe tooling element relative to at least one reference position.
 17. Themethod of claim 1 wherein step b) includes creating the overlay toinclude a plurality of markings identifying positions of a plurality ofportions of the tooling element relative to at least one referenceposition.
 18. The method of claim 1 wherein step b) includes creatingthe overlay to include a plurality of markings identifying positions ofa plurality of portions of the tooling element relative to at least onemarking identifying at least one reference position.
 19. The method ofclaim 1 wherein step b) includes creating the overlay including the atleast one marking identifying the position of at least the portion ofthe tooling element relative to at least two reference positions. 20.The method of claim 1 wherein the step b) creating the overlay includesidentifying the position of at least the portion of the tooling elementby way of a computer input.
 21. The method of claim 1 further comprisingthe step of storing the overlay in a memory of a computer of theultrasonic bonding system.
 22. An ultrasonic bonder comprising: asupport structure configured to support a workpiece during an ultrasonicbonding operation; a clamp finger for securing a portion of theworkpiece against the support structure during the ultrasonic bondingoperation; an imaging system; and an overlay configured to be imaged bythe imaging system in relation to at least one of the support structureand the clamp finger.
 23. The ultrasonic bonder of claim 22 wherein theoverlay includes a computerized overlay configured to be viewed on adisplay of the ultrasonic bonder.
 24. The ultrasonic bonder of claim 22wherein the overlay is configured to assist an operator of theultrasonic bonder to align at least one of the support structure and theclamp finger in connection with a position of the support structure orthe clamp finger included in the overlay.